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/*-
* Public Domain 2014-2016 MongoDB, Inc.
* Public Domain 2008-2014 WiredTiger, Inc.
*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package com.wiredtiger.db;
import java.io.ByteArrayInputStream;
import java.lang.StringBuffer;
import com.wiredtiger.db.PackUtil;
import com.wiredtiger.db.WiredTigerPackingException;
/**
* An internal helper class for consuming pack format strings.
*
* Applications should not need to use this class.
*/
public class PackFormatInputStream {
protected String format;
protected int formatOff;
protected int formatRepeatCount;
/**
* Constructor for a format stream.
*
* \param format the encoded format backing string.
*/
protected PackFormatInputStream(String format) {
this.format = format;
formatOff = 0;
formatRepeatCount = 0;
}
/**
* Standard toString - returns the string used during construction.
*/
public String toString() {
return format;
}
/**
* Returns the approximate count of elements left in the format.
* This method does not account for repeat counts or string length
* encodings - so should be used as a guide only.
*/
public int available() {
return format.length() - formatOff + formatRepeatCount;
}
/**
* Reset the current stream position.
*/
public void reset() {
formatOff = 0;
formatRepeatCount = 0;
}
/**
* Return the decoded type for the next entry in the format stream. Does
* not adjust the position of the stream.
*/
protected char getType()
throws WiredTigerPackingException {
if (formatOff >= format.length()) {
throw new WiredTigerPackingException(
"No more fields in format.");
}
String fieldName;
boolean lenOK = false;
int countOff = 0;
while (PackUtil.PackSpecialCharacters.indexOf(
format.charAt(formatOff + countOff)) != -1) {
countOff++;
}
// Skip repeat counts and sizes
while (Character.isDigit(format.charAt(formatOff + countOff))) {
countOff++;
}
return format.charAt(formatOff + countOff);
}
/**
* Check to see if the next entry is compatible with the requested type.
*
* \param asking the format type to match.
* \param consume indicates whether to update the stream position.
*/
protected void checkType(char asking, boolean consume)
throws WiredTigerPackingException {
char expected = getType();
if (Character.toLowerCase(expected) != Character.toLowerCase(asking))
throw new WiredTigerPackingException(
"Format mismatch. Wanted: " + asking + ", got: " + expected);
if (consume) {
consume();
}
}
/**
* Move the format stream position ahead one position.
*/
protected void consume() {
if (formatRepeatCount > 1) {
--formatRepeatCount;
} else if (formatRepeatCount == 1) {
formatRepeatCount = 0;
++formatOff;
} else {
while (PackUtil.PackSpecialCharacters.indexOf(
format.charAt(formatOff)) != -1) {
++formatOff;
}
// Don't need to worry about String or byte array size counts
// since they have already been consumed.
formatRepeatCount = getIntFromFormat(true);
if (formatRepeatCount == 0) {
++formatOff;
}
}
}
/**
* Decode an integer from the format string, return zero if not starting
* on a digit.
*
* \param advance whether to move the stream position.
*/
private int getIntFromFormat(boolean advance) {
int valueLen = 0;
int countOff;
for (countOff = 0;
Character.isDigit(format.charAt(formatOff + countOff));
countOff++) {
valueLen *= 10;
valueLen += Character.digit(format.charAt(formatOff + countOff), 10);
}
if (advance) {
formatOff += countOff;
}
return valueLen;
}
/**
* Retrieve a length from the format string. Either for a repeat count
* or a string length. Return one if no explicit repeat count.
*
* \param advance whether to move the stream position.
*/
protected int getLengthFromFormat(boolean advance) {
int valueLen = getIntFromFormat(advance);
if (valueLen == 0) {
valueLen = 1;
}
return valueLen;
}
/**
* Return whether there is an explicit length indicated in the format
* string.
*/
protected boolean hasLength() {
return (getIntFromFormat(false) > 0);
}
}
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